The two bikes you have on your shortlist could not be more different. There is enough information on the web about the particular virtues of each model but, as they are so different, I would suggest that you get a test ride on both of them to see which one suits you best.

Which bike
Why are they different? With what I've read the z1000sx has more grunt but both good sports tourers!! Wondered more about running costs ie:- minor,major service costs and mileage intervals! Any help would be grateful rather than trolling the net at the minute! Cheers

* The VFR was first released in 2003 making the model at least 12 years old whereas the Z1000 is a much more modern machine. The Z1000 has inverted forks and radial brakes but the VFR has much more standard fare. I could go on but you get the point. In many ways they could not be more different.

I agree they are both good bikes and may even both be classed as sports-tourers but they are nothing alike - either in specification or riding experience.

Agree with Marcus...
The two bikes are quite different in their riding position and quality. The VFRs are lovely beasts (I'm in love with a white one that purrs/thuds past me every two days or so when walking to the shop) beautifully finished, gorgeous sound, great lights (twin dip lights), good design and detailing (easy chain adjustment thanks to single swing arm and centre stand, large fuel tank, comfy seat) but have a riding position that's more sporty than the Z1000SX. They can be very expensive to service and are very thirsty compared to most modern bikes. Not ridden one but power wise they only(?) have 100 BHP. Not sure of the effect of that for some... Think aging super model... If you can buy one with luggage included to keep your costs down...
The Z1000SX can only be cheaper to service (since the VFR is the most expensive I have come across and the Z1000 has a simple in line 4) and is not as well finished or designed but is probably faster and more efficient.
Riding position is more touring than the VFR - Think a bigger ER6F (and that is a good thing). I would struggle to be as proud of it as the Honda though.